Pakistan's Interior Minister Chaudhry Nisar Ali Kahn has complained about a U.S. drone strike targeting Afghan Taliban leader Mullah Akhtar Mansur -- saying that the attack on the Taliban leader while he was in Pakistan was not legal.

The Pentagon has said Mansur was targeted by the May 21 drone strike under U.S. rules of engagement that allow "defensive strikes" against people engaged in activity that poses "specific, imminent threats" to U.S. and coalition troops in Afghanistan.

But Khan said it is "against international law" for the U.S. government to say that "whoever is a threat to them will be targeted wherever they are."

U.S. President Barack Obama said on May 23 that Mansur was killed in the drone strike near Quetta just south of Afghanistan’s border.

But Khan said on May 24 that DNA tests were necessary to confirm the identity of the badly charred body thought to be that of Mansur.